Type of Fluids and VolumeExpanderNabilah060 100 814H4
Body Fluids CompositionTotal body water= 60% (male)|50%(female) x body wt = 0.5 X 70 = 35 litersECF=1/3 ICF=2/30.33 X 35 = 11.6 liters 0.66 X 35 = 23.3 litersBlood=1/4 (ECF)0.25 X 10.5 = 2.625 liters
Types of IV FluidsThree main types of IVF: Isotonic fluids Hypotonic fluids Hypertonic Fluids
Isotonic Fluids Osmolarity is similar to that of serum. These fluids remain intravascularly mommentarily, thus expanding the volume. Helpful with patients who are hypotensive or hypovolemic. Risk of fluid overloading exists. Therefore, be careful in patients with left ventricular dysfunction, history of CHF or hypertension.
1 Liter 0.9% saline Total body waterECF=1 liter ICF=0 Interstitial=3/4 of ECF=750mlIntravascular=1/4 ECF=250 ml
Hypotonic Fluids Less osmolarity than serum (meaning: less sodium ion concentration than serum) These fluids DILUTE serum thus decreasing osmolarity. Water moves from the vascular compartment into the interstitial fluid compartment interstitial fluid becomes diluted osmolarity decreases water is drawn into adjacent cells. Less than 10% remain intravascular, inadequate for fluid resuscitation Caution with use because sudden fluid shifts from the intravascular space to cells can cause cardiovascular collapse and increased ICP in certain patients.
1 liter 5% Dextose Total body water=1 liter ECF=1/3 = 300ml ICF=2/3 = 700mlIntravascular=1/4 of ECF~75ml
Hypertonic Fluids These have a higher osmolarity than serum. These fluids pull fluid and sometimes electrolytes from the intracellular/interstitial compartments into the intravascular compartments. Useful for stabilizing blood pressure, increasing urine output, correcting hypotonic hyponatremia and decreasing edema. These can be dangerous in the setting of cell dehydration.
Two Main Groups of Fluids Crystalloids Colloids
Crystalloids Clear solutions –fluids- made up of water & electrolyte solutions; small molecules. These fluids are good for volume expansion. However, both water & electrolytes will cross a semi-permeable membrane into the interstitial space and achieve equilibrium in 2- 3 hours. Remember: 3mL of isotonic crystalloid solution are needed to replace 1mL of patient blood. This is because approximately 2/3rds of the solution will leave the vascular space in approx. 1 hour.
Crystalloids Continued Advantages: ◦ Inexpensive ◦ Easy to store with long shelf life ◦ Readily available with a very low incidence of adverse reactions ◦ Variety of formulations available that are effective for use as replacement fluids or maintenance fluids A major disadvantage is that it takes approximately 2-3 x volume of a crystalloid to cause the same intravascular expansion as a single volume of colloid.
Colloids Colloids are large molecular weight solutions (nominally MW > 30,000 Daltons) Macromolecular substances made of gelatinous solutions which have particles suspended in solution and do NOT readily cross semi-permeable membranes or form sediments. Their high osmolarity, are important in capillary fluid dynamics because they are the only constituents which are effective at exerting an osmotic force across the wall of the capillaries. These work well in reducing edema draw fluid from the interstitial and intracellular compartments into the vascular compartments. Initially these fluids stay almost entirely in the intravascular space for a prolonged period of time
Colloids ContinuedThe general problems with colloid solutions are: Much higher cost than crystalloid solutions Small but significant incidence of adverse reactions Gelatinous properties cause platelet dysfunction and interfere with fibrinolysis and coagulation factors thus possibly causing Coagulopathy in large volumes. These fluids can cause dramatic fluid shifts which can be dangerous if they are not administered in a controlled setting.